Towards remote manipulation of lightning using “broken wire” generated by high power lasers
Prof. Arie Zigler The Hebrew University of Jerusalem, Jerusalem, Israel
Web page link
Abstract:
Remote manipulation of lightning in atmospheric conditions has been the subject of intense scientific research for many decades. Remotely controlling of lightning, requires conducting channels exceeding the length of several tens of meters and microsec lifetime in vicinity of the charged cloud. High power, ultrashort-pulse lasers are considered attractive in generating plasma channels in air. However, two fundamental obstacles, the limited length and lifetime of plasma channels prevented their realization to this date.
A powerful femtosecond laser pulse undergoing beam filamentation leaves channels of ionized air in its wake. The length of each of these plasma filaments is about 1m and initial plasma density is several times 1016cm-3 decaying by an order of magnitude on a timescale of 3nsec.
By controlling the shot to shot randomness, the number and the position of many filaments initiated by a single laser pulse we experimentally generated a long concatenated high-density plasma channel exceeding the length of 15m. Lifetime of these plasma filaments is demonstrated to be extended by more than an order of magnitude. We reveal the physical mechanism behind the prolongation of plasma lifetime and demonstrate the preferential conditions for lifetime extension. These two methods, namely length and lifetime prolongation were experimentally combined into a optical setup demonstrating an elongated and long-lived high-density plasma channel generated by lasers in air.
Ecole de Physique
Auditoire Stueckelberg
Quai Ernest-Ansermet 24
1205 Genève